This invention relates to an arrangement for the intermediate storage of a yarn, particularly during a repair of a yarn breakage on a spinning arrangement. A drivable storage roller is provided which receives the yarn helically and which is preceded by a continuously yarn-delivering delivery device and followed by a stoppable withdrawal device and which, in the area of its end facing the withdrawal device, is equipped with a yarn driving device which projects into the travelling path of the yarn.
In the case of an arrangement of the initially mentioned type (European Patent Document EP 108 195 B1), the yarn moves onto the storage roller at a predetermined point. This point is formed by a yarn advancing disk which is sloped with respect to the shaft of the storage roller in order to advance the helically wound-up yarn layers in such a manner that space is created for the next yarn layers. In this case, the helical yarn loops slide on the surface of the storage roller in the axial direction. Such a sliding is not acceptable for all types of yarn because it may damage the yarn. This occurs particularly in cases in which yarns having a relatively low strength and/or yarns having a relatively high proportion of synthetic fibers are processed.
It is also known (German Patent Document DE 38 17 222 A1) to provide, in the case of an arrangement for the intermediate storage, a pneumatic yarn storage device in which the yarn is stored in several loops.
It is an object of the invention to develop an arrangement of the initially mentioned type such that a controlled receiving of the helical yarn layers is ensured, in which case sliding movements between the yarn and the surface of the storage roller are avoided.
This object is achieved according to preferred embodiments of the invention in that a yarn transfer device is assigned to the storage roller which has a yarn guiding element deflecting the yarn coming from the delivery device to the storage roller and which can be moved in the axial direction of the storage roller by means of a driving device.
The yarn transfer device provides that the yarn loops are deposited on the storage roller in a regular fashion without being slidingly displaced in the axial direction of the storage roller. In addition, the stored yarn can easily be withdrawn by way of the end of the storage roller.
In a development of the invention, it is provided that the drives of the storage roller and of the yarn transfer device are coupled to one another. This ensures in a simple manner that the helical yarn loops can be deposited at a defined distance with respect to one another.
In an advantageous embodiment of the invention, it is provided that the yarn transfer device has a spindle nut which is arranged on a drivable threaded spindle extending in parallel to the storage roller. In an expedient further development, it is provided that the yarn transfer device is guided on the storage roller. As a result, a securing of the yarn transfer device is obtained with respect to twisting.
In a further development of the invention, it is provided that the yarn driving device of the storage roller can be changed over between an operative state and an inoperative state. The changing-over from the operative to the inoperative state takes place when the storage roller is to be emptied again, which then results in the advantage that the driving device does not impair the emptying. Thus, it is also ensured that no impermissibly high yarn tensions occur during the emptying.
In a further development of the invention, it is provided that the circumferential surface of the storage roller is provided with a helically extending profiling. This profiling provides that the yarn loops are guided separately.
In a further development of the invention, it is provided that, between the storage roller and the withdrawal device, a yarn guiding device is provided which is arranged coaxially with respect to the storage roller and which can be applied to the travelling yarn. As a result, it is ensured that, when the yarn is withdrawn by way of the end of the storage roller, the same withdrawal angle is maintained.
In a further development of the invention, it is provided that a compensating device is provided between the yarn guiding device and the withdrawal device. As a result, the circumstance is taken into account that the yarn withdrawn from the storage roller forms a balloon by means of which the yarn tension is increased.
In a further development of the invention, it is provided that the yarn transfer device is equipped with a yarn detector. This yarn detector emits a signal when the yarn leaves the yarn transfer device and thus also the storage roller; that is, when the yarn storage device is emptied. This signal can then be utilized in such a manner that then the yarn withdrawal speed is reduced from the increased speed used for the emptying of the storage device to the normal withdrawal speed.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.